manus_continuum_granular1

manuscript files for first continuum-till paper
git clone git://src.adamsgaard.dk/manus_continuum_granular1
Log | Files | Refs

commit b01e955ab061562aeafed78f87ba7b456f65544b
parent d915a43dd0447d3d1bdd55351a8d3f06bbb3fbcf
Author: Anders Damsgaard <anders@adamsgaard.dk>
Date:   Thu, 26 Sep 2019 20:29:26 +0200

Add new figures and pulse tests

Diffstat:
MBIBnew.bib | 35+++++++++++++++++++++++++++++++++++
Mcontinuum-granular-manuscript1.tex | 44+++++++++++++++++++++++++++++++++++++-------
Mexperiments/fig5.pdf | 0
Mexperiments/fig5b.pdf | 0
Aexperiments/pulse-square-fig4b.pdf | 0
Aexperiments/pulse-triangle-fig4b.pdf | 0
6 files changed, 72 insertions(+), 7 deletions(-)

diff --git a/BIBnew.bib b/BIBnew.bib @@ -9050,3 +9050,38 @@ Winton and A. T. Wittenberg and F. Zeng and R. Zhang and J. P. Dunne}, title = {In situ measurements of the resistivity of Antarctic sea ice}, journal = {Cold Regions Sci. Technology} } + +@article{Hart2019, + doi = {10.1038/s41467-019-09547-6}, + year = 2019, + month = {apr}, + publisher = {Springer Nature}, + volume = {10}, + number = {1}, + author = {J. K. Hart and K. Martinez and P. J. Basford and A. I. Clayton and B. A. Robson and D. S. Young}, + title = {Surface melt driven summer diurnal and winter multi-day stick-slip motion and till sedimentology}, + journal = {Nature Commun.} +} +@article{Bougamont2019, + doi = {10.1029/2018jf004707}, + year = 2019, + month = {jan}, + publisher = {American Geophysical Union ({AGU})}, + volume = {124}, + number = {1}, + pages = {80--96}, + author = {M. Bougamont and P. Christoffersen and I. Nias and D. G. Vaughan and A. M. Smith and A. Brisbourne}, + title = {Contrasting Hydrological Controls on Bed Properties During the Acceleration of Pine Island Glacier, West Antarctica}, + journal = {J. Geophys. Res.: Earth Surf.} +} +@article{Melanson2013, + doi = {10.1016/j.quascirev.2013.02.017}, + year = 2013, + month = {may}, + publisher = {Elsevier {BV}}, + volume = {68}, + pages = {154--174}, + author = {A. Melanson and T. Bell and L. Tarasov}, + title = {Numerical modelling of subglacial erosion and sediment transport and its application to the North American ice sheets over the Last Glacial cycle}, + journal = {Quat. Sci. Rev.} +} diff --git a/continuum-granular-manuscript1.tex b/continuum-granular-manuscript1.tex @@ -49,25 +49,47 @@ We show that past pulses in water pressure can transfer shear away from the ice- \section{Introduction}% \label{sec:introduction} -Subglacial sediment deformation is in many settings a constituent of primary importance to glacier flow \citep[e.g.][]{Boulton1974, Engelhardt1990, Fischer1994, Truffer2006}. -The mechanical behavior of the sediment is long debated \citep[e.g.][]{Alley1986, Boulton1987, Kamb1991, Iverson1995, Hooke1997, Tulaczyk2001, Fowler2003, Iverson2010}. -The earliest applied till rheologies were viscous in nature, allowing the formulation of analytical solutions to the coupled ice-till problem \citep[e.g.][]{Walder1994, Hindmarsh1999, Fowler2000}, and a glacier sliding law similar to hard-bed sliding laws without cavitation \citep[e.g.][]{Budd1979}. +Subglacial sediment deformation is in many settings of primary importance to glacier flow \citep[e.g.][]{Boulton1974, Engelhardt1990, Fischer1994, Truffer2006}. +The mechanical behavior of the sediment is long debated \citep[e.g.][]{Alley1986, Boulton1987, Kamb1991, Iverson1995, Hindmarsh1997, Hooke1997, Fowler2003, Iverson2010, Hart2011}. +Early on, till was assumed to be viscous \citep{Boulton1987} which allowed the formulation of analytical solutions to the coupled ice-till problem \citep[e.g.][]{Walder1994, Hindmarsh1999, Fowler2000}. +Resultant glacier sliding laws are similar to hard-bed sliding laws without cavitation \citep[e.g.][]{Budd1979}. +However, laboratory experiments on tills \citep[e.g.][]{Kamb1991, Iverson1998, Tulaczyk2000, Rathbun2008, Iverson2010, Iverson2015} +and field observations \citep[e.g.][]{Iverson1995, Hooke1997, Tulaczyk2006} +have concluded that till strength is nearly rate-independent, adhering to Mohr-Coulomb plasticity. + +\citet{Damsgaard2016} showed that creep before failure is rate dependent, + +\citet{Hart2011} argued that the rheology is dependent on water pressure. + +% remote-sensing inversion and modeling +% Gudmundsson, Robel, Minchew, Winberry2011, Walker2013, Thompson2014, Rosier2015, Ritz2015, Bindschadler2003 -% Iverson1998 -% Tulaczyk2001, Tulaczyk2006 % Hart2017, Hart2019 % Damsgaard2013 % Iverson2015 % Damsgaard2016 +% Joughin2010 + % Tsai, Schoof +The \emph{undrained plastic-bed} model by \citet{Tulaczyk2000b} uses the relationship between sediment void-ratio, effective normal stress, and shear stress to link hydraulics with till strength. +This parameterization has been included in ice sheet models, successfully reproducing transient flow dynamics \citep{Bougamont2011, vanDerWel2013, Gillet-Chaulet2016, Bougamont2019}. + +\citet{Schoof2010} produced a reguralized form of the Coulomb friction sliding law, making it feasible to simulate sliding over plastic tills in ice-sheet models. +However, + + +\citet{Iverson2001} demonstrated that perturbations in effective stress at depth can distribute deformation away from the ice-bed interface. + + % Tarasov? +\citep{Melanson2013}. + + -% remote-sensing inversion and modeling -% Gudmundsson, Robel, Minchew, Winberry2011, Walker2013, Thompson2014, Rosier2015, Ritz2015, Bindschadler2003 % Minchew2019 @@ -348,6 +370,14 @@ The shear velocities during the first cycle ($t<1$ d) is slightly different from \end{center} \end{figure} +\begin{figure}[htbp] + \begin{center} + \includegraphics[width=0.49\textwidth]{experiments/pulse-triangle-fig4b.pdf} + \includegraphics[width=0.49\textwidth]{experiments/pulse-square-fig4b.pdf} + \caption{\label{fig:pulse}% + } + \end{center} +\end{figure} \begin{figure*}[htbp] \begin{center} diff --git a/experiments/fig5.pdf b/experiments/fig5.pdf Binary files differ. diff --git a/experiments/fig5b.pdf b/experiments/fig5b.pdf Binary files differ. diff --git a/experiments/pulse-square-fig4b.pdf b/experiments/pulse-square-fig4b.pdf Binary files differ. diff --git a/experiments/pulse-triangle-fig4b.pdf b/experiments/pulse-triangle-fig4b.pdf Binary files differ.